JPH1167443A - Lens-shape dielectric loading applicator for focusing micro wave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a micro wave applicator which can easily focus a micro wave on a heated body to heat the body, by mounting a dielectric having the same permittivity as that of the heated body in a heated dielectric, and combining with a radiator. SOLUTION: Micro wave oscillated from a micro wave oscillating source 4 is transmitted in an electromagnetic horn 3 to be expanded, is focused by a lens formed with a dielectric 2 having the same relative permittivity as that of a heated dielectric 1, and efficiently form a focus in the heated dielectric 1 to heat. This can be applied to, for example, heating asphalt for highway maintenance. Micro wave can be focused on the deep part of asphalt to efficiently heat the asphalt by mounting a lens-shape dielectric comprising a dielectric (e.g. a composite of polyethylene and alumina powder) which has the same relative permittivity as that of the heated asphalt and has little loss in the horn 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0101]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an applicator (radiation system) for heating a dielectric substance (in some cases, a magnetic substance or a combination thereof) when applying microwave power to an industrial or medical field.

[0092]

2. Description of the Related Art Conventionally, it has been attempted to arrange a metal or dielectric lens in an electromagnetic horn, irradiate a dielectric to be heated, and perform concentrated heating.
_r is large (ε _r > 3), it is difficult to concentrate the microwaves, and the horn system (2) + (3) and the dielectric to be heated (1) are separated as shown in FIG. Reflection occurs at
The frequency characteristics were poor, and it was difficult to concentrate short distance points from the surface of the dielectric to be heated.

[0093]

As described above, for example, when only the surface layer and the base layer (） 20 cm) of an asphalt pavement road are heated to about 100 ° C. using microwaves, and solidification or peeling is performed in a short time, In the conventional method using the electromagnetic horn, most of the micro-power is reflected at the boundary surface and penetrates deeper, and the efficiency is low, so that it is difficult to put the electric power to practical use. Also, when a metal lens or the like used for hyperthermia cancer treatment is used as an applicator, the reflection at the boundary surface is large and it is difficult to concentrate on a shallow portion, which is inefficient.

[0093]

In order to solve the above problems, as shown in FIG. 2, a lens-like dielectric (2) having the same dielectric constant ε as the dielectric to be heated (1) (desirably low loss is desirable). )
When (2) is installed in a microwave irradiation source such as an electromagnetic horn so that (1) and (2) can operate integrally, the desired point can be easily obtained without reflection of the boundary as shown in the figure. Microwave If the angle of is θ Designed with. When the focal point F requires a small distance from the boundary surface of (1), as shown in FIG.
In practice, even if there is a gap t between (1) and (2), the dimension of the gap is λ / 1 with respect to the wavelength.
If it is about 0, there is almost no effect on the reflection, and the path of the microwave can be considered to be the same from Snell's law, so there is no problem. The dielectric constant of (2) is 10 times higher than that of (1).
There is no problem if it is about%.

[0056]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A microwave oscillated from a microwave oscillating source (4) propagates while spreading in an electromagnetic horn (3), and has a dielectric (2) having the same dielectric constant as the dielectric to be heated (1). The focus is formed by the lens formed in step (1), and the focal point is efficiently formed inside the dielectric (1) to be heated, and the dielectric is heated.

[0086]

【Example】

[1] FIG. 4 shows an embodiment of an asphalt microwave heating applicator for road repair. Opening surface 16x20cm, 1⊆40 for frequency 2.45GHz
Within an electromagnetic horn of about cm, the E-plane electromagnetic field may be considered to have approximately the same amplitude and phase. Therefore, as described above, (1)
(2) Lens-like dielectric (2) made of a dielectric material (e.g., a composite of polyethylene and alumina powder, ε _r = 3.9) having substantially the same dielectric constant as the heated asphalt
By mounting the inside of the horn, the microwave can be concentrated at a depth of about 5 to 10 cm from the boundary surface of (1), and the asphalt can be efficiently heated.

[2] Thickness 1 carried by conveyor belt etc. as shown in FIG.
When microwaves are heated by a horn equipped with (2) having substantially the same dielectric constant on soil of 0 to 20 mm, the soil can be easily improved by the sterilizing action of the microwaves.

FIG. 6 shows an embodiment of a microwave hyperthermia. I is a heated object (human body), and a solid or a liquid dielectric placed in a container whose dielectric constant can be considered to be substantially equivalent thereto is mounted in the horn. Microwaves can be concentrated and heated at a desired depth.

007

According to the present invention, it is possible to easily focus and heat the microwave into the object to be heated, repair asphalt for road repair, sterilize the soil, microwave hyperthermia, etc. for industrial and civil engineering purposes. It greatly contributes to agricultural, industrial, medical, etc.

[Brief description of the drawings]

FIG. 1 shows a conventional radio wave focusing method in microwave heating.

FIG. 2 is a sectional view of the present invention.

FIG. 3 is a sectional view of the present invention when the focal length is reduced.

FIG. 4 is an embodiment of the present invention.

FIG. 5 is an example of the present invention.

FIG. 6 is an example of the present invention.

[Description of Signs] (1) is a dielectric to be heated, (2) is a dielectric having the same dielectric constant as (1), (3) is an electromagnetic horn, (4) is a microwave oscillation source, and (t) is The gap between the heated dielectric and the lens,
(D) is the thickness of the lens.

Claims (1)

[Claims] 1. A microwave applicator in which a microwave having the same dielectric constant as a dielectric to be heated is mounted on the dielectric to be heated and combined with a radiator so that microwaves can be focused and heated.